Dynamic topology

With Dynamic on, the brush adds triangles where it needs detail and removes them where it doesn't, as ZBrush's Sculptris Pro and Blender's Dyntopo do. Pull a sphere out into horns, ears or fingers and the new shapes get triangles of their own instead of stretched ones; block in a creature from a ball without remeshing first.

Turn it on#

Then sculpt as usual. Every brush works with it except Move (it drags the surface without remeshing), the mask and paint brushes, and the stamping strokes DragRect and DragDot (so VDM stamps don't remesh either). Smooth remeshes towards larger triangles, so smoothing also simplifies, as in ZBrush.

How big the triangles get#

By default the triangle size follows the brush size on screen, as in Sculptris Pro: zoom in or make the brush smaller for finer triangles, zoom out or make it bigger for coarser ones. At Detail 50 an edge is about an eighth of the brush radius; Detail 100 makes them about three times smaller, Detail 0 three times bigger.

With Constant detail on, every stroke aims for the same size whatever the zoom and brush, set by Detail relative to the size of the mesh (at 50, about a hundredth of its bounding box diagonal). Use it to bring a whole model to an even density, or to keep the density while you change brush sizes. It is a preference: Store Config (Ctrl+Shift+I) keeps it.

Under the brush, edges longer than the target are split, edges much shorter are merged away, and the new triangles are evened out. Outside the brush nothing changes, so you can have big triangles on the back of a head and fine ones around the eyes.

What it keeps and what it doesn't#

• Symmetry. With X (or Y, Z) symmetry on, both sides are remeshed together and get mirrored triangles, not just mirrored shapes.
• Mask and visibility. Fully masked and hidden parts are left alone. Partly masked areas are remeshed but move less, as usual.
• Borders. Open edges and the borders between polygroups stay where they are; their vertices only slide along them. New triangles take the polygroup of the triangle they came from.
• Polypaint, mask values and sculpt layers are carried onto new vertices (blended between their neighbours).
• Quads under the brush become triangles. The rest of the mesh keeps its quads.
• UVs are dropped the first time a stroke remeshes a SubTool (the status bar says so), since the new triangles have none. Undo brings them back. Unwrap again with Auto UV when you are done.

Subdivision levels#

Dynamic topology works on meshes without subdivision levels, as in ZBrush. On a SubTool with levels, Dynamic stays off and the status bar says why: go to the level you want to keep and use Del Lower and Del Higher in Tool > Geometry first. If you turn it on and then pick a SubTool that has levels, strokes sculpt it without remeshing.

A good workflow: block in with Dynamic, then QRemesh or Voxel Remesh for an even base, Divide for levels, and sculpt the fine detail on them.

Undo and speed#

Each stroke is one undo step. Undo puts every triangle back exactly, and it only keeps the part of the mesh the stroke changed, so it costs little memory even on millions of triangles (a few megabytes per stroke).

Dynamic topology is fastest on meshes of up to a few million triangles. On the benchmark computer (an M1 Pro), a dab with a medium brush on a one-million-triangle sphere takes 9 to 13 milliseconds including the screen update; undoing a stroke on such a mesh takes about a tenth of a second. A very big brush over very small triangles merges them over several dabs rather than all at once, to keep the brush responsive. See Performance and big meshes.

From a script#

dyntopo enabled=true detail=60
stroke points="0.3,0.6,1 0.5,0.4,1" brush=SnakeHook radius=0.2 symmetry=x
dyntopo enabled=false

dyntopo without arguments reports the settings; constant=true switches to a constant detail size. It works the same from the console, sculptforge-cli, MCP and Python. See Scripting and automation.

See also#

• Sculpting and brushes
• Subdivision levels
• Subdivide, remesh, decimate and LODs
• Coming from ZBrush